>how is propaganda so effective despite the efforts of intellectuals
Efforts to achieve what exactly? Intellectuals are scholars who care more about advancing their career than ineracting with the day to day struggles of humanity. Whether that involves niche academic pursuits, fame, wealth, it doesn't matter; they are equally far removed from the society who pampers and enables them.

They are not politicians. They are not generals. They are not engineers. They are not farmers. They are not representatives of any class but their own, and care little for any criticism or judgement from anyone but themselves, except when it threatens their livelihood.

Did you really think these people are willing, much less capable, to lead any charge against the market forces which produce these media narratives? The same forces which enable their existence at all? No, their "efforts" are tantamount to sending thoughts and prayers on facebook. Sure, it's got more citations, and maybe even there is some truth to it,
but their work will never inspire any revolution or real change which could not, and would not, come about without them.

In short, all they are good for is to provide some fancy words in thr pamphlet carried by the idiots following the flavor-of-the-decade ideology.